1. Field of Invention
The invention relates to an ink jet recording apparatus that performs printing by ejecting an ink droplet.
2. Description of Related Art
There have been conventional recording apparatuses, such as printers, that perform printing on a recording medium, such as sheets and overhead transparency films. The recording apparatuses include a recording head for performing printing on the recording medium. For example, an ink jet head, a dot impact head, and a thermal transfer head are used as such a recording head. Among them, the ink jet head has a relatively simple structure and can perform printing at high speeds with high quality.
The ink jet head has a nozzle surface in which a plurality of nozzles that eject ink droplets are formed. If foreign substances, such as waste ink and dust, deposit in the vicinity of the nozzles, appropriate ink ejection may not be performed. For example, an ink droplet may be ejected in an improper direction from the nozzle or may not come out from the nozzle. In such cases, ink ejection recovery processing is performed on the nozzle surface to eliminate factors in preventing ejection of ink droplets.
For implementing the ink ejection recovery processing, a wiping mechanism is provided to eliminate the foreign substances adhering to the nozzle surface by wiping the nozzle surface of the ink jet head.
The nozzle surface is generally made with an ink-repellent coating. If the nozzle surface is strongly wiped by the wiping mechanism, the foreign substances on the nozzle surface can be cleanly removed. However, as a result of this, an ink-repellent coating easily comes off, thereby decreasing durability of the nozzle surface. On the other hand, if the wiping force of the wiping mechanism against the nozzle surface is weak, then the foreign substances, including solidifying ink, may not be completely removed from the nozzle surface.
The invention provides an ink jet recording apparatus having a wiping mechanism that eliminates foreign substances on a nozzle surface without decreasing durability of an ink-repellent coating on the nozzle surface.
According to one aspect of the invention, an ink jet recording apparatus includes a recording head, a wiping mechanism, a drive device and a controller. The recording head performs printing on a recording medium by ejecting ink from at least one nozzle located on a nozzle surface. The wiping mechanism has a first and a second wiping member that can contact the nozzle surface. In the wiping mechanism, at least one of the first and second wiping members wipes and cleans the nozzle surface of the recording head. The drive device moves the wiping mechanism and the recording head in relationship to each other to allow the wiping mechanism to wipe the nozzle surface. The controller selectively performs either a normal wiping operation for wiping the nozzle surface using the first wiping member with a first wiping force, or a powerful wiping operation for wiping the nozzle surface using at least the second wiping member with a second wiping force stronger than the first wiping force used during the normal wiping operation, in accordance with operational status of the ink jet recording apparatus.
According to another aspect of the invention, a wiping method is performed in an ink jet recording apparatus that includes a recording head with at least one nozzle that performs printing on a recording medium by ejecting ink from the nozzle, a wiping mechanism that wipes and cleans a nozzle surface of the recording head, in which the nozzle is formed, using first and second wiping members and a drive device that relatively moves the wiping mechanism and the recording head with respect to each other to allow the wiping mechanism to wipe the nozzle surface. In the wiping method, the operational status of the ink jet recording apparatus is analyzed. In accordance with analytical results, either a normal wiping operation in which the nozzle surface is wiped using the first wiping member with a first wiping force against the nozzle surface, or a powerful wiping operation in which the nozzle surface is wiped using at least the second wiping member with a second wiping force stronger than the first wiping force, is selectively performed.
With this structure, during the normal wiping operation, the nozzle surface is wiped using the first wiping member. Therefore, during the normal wiping operation, foreign substances on the nozzle surface is wiped and removed therefrom by a force that is weaker than the force used during the powerful wiping operation. During the powerful wiping operation, the nozzle surface is wiped using the second wiping member with a force that is stronger than that at the normal wiping operation. Accordingly, the foreign substances, including solidifying ink on the nozzle surface, can surely be eliminated from the nozzle surface.